Three-wheeled strollers have a significant advantage over their four wheeled predecessors in that a three-wheeled configuration is better suited to steer, negotiate bumps and comfortably carry a passenger. The three-wheeled stroller has two wheels positioned at the rear and a single wheel positioned in the front of the stroller, to form a stable tripod. The "jogging" variation of the three-wheeled stroller is simply a three-wheeled stroller designated as a jogging stroller to suggest that the person pushing the stroller can safely jog or run while pushing the stroller over varying terrain.
Several U.S. design and utility patents relate to improvements in three wheeled jogging strollers. U.S. Pat. No. 5,188,389 to Baechler discloses a three wheeled, collapsible or foldable baby stroller having a removable rear hub system. Baechler '389 teaches the removal of the rear hub to aid in collapsible storage and transport. U.S. Pat. No. 5,356,171 to Schmidlin describes another variation of the collapsible jogging stroller. Schmidlin '171 includes hinging frame components to allow the compact folding of the stroller.
These collapsible jogging strollers are easily transportable and convertible to a storage position. However, ease of transport is only one aspect of a well-designed stroller. Many users want a stroller that is collapsible, but can also perform more than a single function. A multifunction stroller provides the economy and convenience of a single stroller while performing various tasks or duties that typically would require separate strollers, each designed for a single, specific purpose.
Trailer strollers are another classification of strollers. Trailer strollers typically attach to the frame of a bicycle and allow a passenger to be towed by a rider of the bicycle. Though it has a function similar to that of jogging strollers, which is the safe carrying of a passenger, the trailer stroller has a significantly different appearance. Typically, the trailer stroller includes only two rear wheels, with an attachment to the bicycle frame as a forward support, which is located in the same position as the front wheel of the jogging stroller.
A significant problem with the conversion between the jogging stroller and the trailer stroller is that two opposing functional characteristics are required for each use. Specifically, the jogging stroller must have a high ground clearance for all terrain operation, for such problems as negotiating street curbs and irregular road or trail surfaces. In contrast, the trailer stroller does not require a curb jumping clearance; and instead it requires a low and stable center of gravity. Tipping a bicycle towed trailer stroller can be disastrous to both the bicycle rider and the stroller's passenger. To function well as both a jogging stroller and a trailer stroller, a convertible jogging stroller and must have the ability to adapt to these opposing use requirements.
For example, U.S. Pat. No. 5,344,171 to Garforth-Bles describes a three-wheeled stroller that is convertible to a trailer. Garforth-Bles '171 includes a wheel fork assembly that can be disassembled and flipped between the configurations shown in FIG. 14 and FIG. 15, therein. This "re-configuration" of the Garforth-Bles '171 stroller converts the stroller from a higher ground clearance jogging stroller to a lower ground clearance trailer stroller. This re-configuration is far from easy. It requires an extensive break down and reassembly of the stroller, including the seat, handle bar and front wheel forks. A convertible stroller is needed that can quickly and easily convert from a jogging to a trailer configuration, without extensive reassembly, as required by Garforth-Bles '171.
U.S. Pat. No. 5,695,208 to Baechlier addresses the problem of stability for jogger strollers that convert to towed trailer strollers with an extensive "conversion assembly." The conversion assembly is a complex upper frame attachment to the jogging stroller that utilizes the seat post and frame of the bicycle to provide counter weighted force downward on the rear wheels of the stroller. To inhibit tipping and rolling, FIGS. 10A and 10B of Baechlier '208 show how the attachment of the conversion assembly lowers the jogging stroller's center of gravity by shifting the terminal ends of the upper frame tubes forward into a trailer configuration. Baechlier '208 again illustrates the great need for a convertible stroller, but still fails to provide a stroller that can quickly and easily convert from a jogging to a trailer configuration, without an expensive additional upper frame assembly.
U.S. Pat. No. Design 379,333 to Jacobs shows a convertible two-seat trailer and jogging stroller that supposedly converts without a complex re-assembly. However, in the jogging configuration, as shown in FIG. 7 of Jacobs '333, the front of the stroller has a very low ground clearance and is ill-suited for rough terrain jogging. Therefore, Jacobs '333 fails to solve the problems addressed by Garforth-Bles '171 and Baechler '208. Jacobs '333 fails to teach how a trailer with a low center of gravity can convert to a three-wheeled jogging stroller that includes a higher ground clearance for rough terrain.